This invention relates to electronic musical instruments, and more particularly to such instruments in which a keyboard is used by a performer to establish a desired harmony.
Electronic musical instruments, such as keyboard-controlled electronic organs, have experienced wide acceptance among musicians. Since many of these instruments are sold to amateurs, manufacturers place special emphasis on the ease of playing. In particular, efforts have been made to simplify the key manipulations required by a performer in order to play accompaniment chords while still permitting the performer to play chords on an accompaniment keyboard.
Examples of a prior art chord recognition systems are shown in U.S. Pat. No. 4,248,118 issued to George R. Hall and Robert J. Hall on Feb. 3, 1981, entitled "Harmony Recognition Technique Application" and assigned to the assignee of the present application (hereinafter referred to as the "'118 patent"). The systems of this patent are capable of detecting the one or more accompaniment keys of an accompaniment keyboard which have been operated by a performer and of making a determination as to the most likely chord root and chord type which the performer wished to sound. These systems also inhibit the sounding of musically invalid chords.
However, as sophisticated as the chord recognition systems of the '118 patent, or other techniques for performing the same function, may be, there are situations where improper key manipulation by a performer can cause undesired outputs. The very sophistication of the system sometimes leads to these erroneous outputs.
Perhaps the most common error of this type results from the sloppy release of the keys operated to sound a given chord. For example, assume that a C major chord made up of the notes C, E, and G was being sounded. If the performer were to release the notes for example in the order G, C, E and, in particular, if the performer were somewhat slow in releasing the E note, the chord recognition systems of the '118 patent would recognize that an E major chord was being called for and would sound this chord even though the playing of such a chord was not intended by the performer. A similar problem could result from any sloppiness in the release of accompaniment keys by the performer because of the fact that the systems of the '118 patent always attempt to determine the most likely chord being selected by the musician when any one or more keys of the accompaniment keyboard are being operated.